Only recently have chip carriers been developed for the packaging of semiconductor chips. A chip carrier is typically comprised of a case having a cavity therein in which a semiconductor chip is fixedly mounted. The semiconductor chip is connected, either by way of solid wires or leads which extend through the case, to bonding pads on the exterior thereof to permit electrical connection to the chip. The case is covered by a lid which is hermetically sealed thereto.
To assure the hermetic seal between the case and the lid, a thin film of a eutectic alloy is deposited in an earlier process on the periphery of a major surface of the lid which will contact its associated case. The alloy will reflow when heated and, upon subsequent cooling, will form the desired seal. The case must be maintained in intimate contact with the lid during heating thereof to prevent the lid from floating during the reflow of the eutectic alloy. In the past, various types of spring clips have been used to apply pressure to the lid and case during heating. One such spring clip has the configuration similar to that of a clothespin where the case and the lid of a chip carrier are held closely to one another between the tines of the spring clip. This type of clip can be configured to typically hold six chip carriers. The clip itself, with the captured chip carriers therein, is ultimately placed in a furnace to reflow the solder to seal the lids onto the cases.
These prior spring clips have not proven satisfactory from the standpoint that they must be manually employed. This necessarily results in slow packaging time and incurs additional expenses in the form of increased labor costs. Secondly, these prior spring clips are not easily adaptable to high volume production of chip carriers because of the additional time required to arrange a sizable number for large-scale simultaneous heating.
Therefore, there is a need for a spring clip adaptable to an automated and a high volume assembly of chip carriers which also holds the lid in intimate contact with the chip carrier cases during the heating thereof.